Anything that didn't go into a portfolio to be sent to their future teacher went home at the end of the year or was tossed then. I don't think it's a big deal to toss them or see if their new teacher possibly wants them. In my school all kids (for the most part) loop from grade to grade so its easy for me to hand important stuff off to the next teacher. That might not be so easy in your school. Don't go nuts- they won't miss it.